US4652953A - Magnetic head actuating mechanism constructed to minimize address effect of disturbance thereto - Google Patents

Magnetic head actuating mechanism constructed to minimize address effect of disturbance thereto Download PDF

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Publication number
US4652953A
US4652953A US06/717,137 US71713785A US4652953A US 4652953 A US4652953 A US 4652953A US 71713785 A US71713785 A US 71713785A US 4652953 A US4652953 A US 4652953A
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United States
Prior art keywords
magnetic head
actuating mechanism
pivot
actuator arm
capstan
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US06/717,137
Inventor
Kanji Sakurai
Hideo Tsumura
Chiaki Kawamura
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Assigned to MITSUBISHI DENKI KABUSHIKI KAISHA reassignment MITSUBISHI DENKI KABUSHIKI KAISHA ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KAWAMURA, CHIAKI, SAKURAI, KANJI, TSUMURA, HIDEO
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B33/00—Constructional parts, details or accessories not provided for in the other groups of this subclass
    • G11B33/02—Cabinets; Cases; Stands; Disposition of apparatus therein or thereon
    • G11B33/08—Insulation or absorption of undesired vibrations or sounds
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/54—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head into or out of its operative position or across tracks
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/48—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed
    • G11B5/54—Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads, e.g. for scanning the record carrier to increase the relative speed with provision for moving the head into or out of its operative position or across tracks
    • G11B5/55—Track change, selection or acquisition by displacement of the head
    • G11B5/5521—Track change, selection or acquisition by displacement of the head across disk tracks

Definitions

  • the present invention relates to a magnetic head actuating mechanism for a magnetic disk apparatus or the like, and more particularly to a magnetic head actuating mechanism for actuating a rotary magnetic head which moves along a circular arc on a pivot.
  • FIG. 1 there are shown a magnetic disk 1, a magnetic head 2 which is floated slightly over the magnetic disk 1 as the magnetic disk rotates, to write data in or to read data from the magnetic disk 1, an actuator arm 3 mounted with the magnetic head 2 and adapted to turn on a bearing 4, and a capstan 5 mounted on the shaft of a driving motor.
  • the capstan 5 winds or unwinds a thin metallic band 6.
  • One end of the band 6 is fixed to a leaf spring 7 for preloading the band 6 and the other end of the band 6 is fixed to the actuator arm 3.
  • this magnetic head actuating mechanism Upon the actuation of the magnetic disk 1 for rotation, the magnetic head 2 is floated up by a distance of approximately 0.5 ⁇ m for reading or writing data. After the magnetic head 2 has been floated up, the capstan 5 is rotated to move the magnetic head 2 to bring the magnetic head 2 into alignment with each one of the data tracks formed in concentric circles on the magnetic disk 1. The magnetic head 2 moves along a circular arc on the bearing 4 of the actuator arm 3.
  • the magnetic disk apparatus needs to be equipped with some protective mechanism which is capable of checking the movement of the magnetic head 2 even if a disturbance within a range certified for the apparatus is applied to the apparatus.
  • the maximum disturbance is such a shock as applied to the apparatus when the packed apparatus is dropped from a predetermined height, and the maximum disturbance is as large as around 30 G.
  • the magnetic head 2 is placed at a shipping position outside the data area during transportation and, in many cases, the magnetic head 2 is held at the shipping position by means of a locking mechanism.
  • the conventional magnetic disk apparatus is constituted as described hereinbefore, some protective mechanism has been necessary to restrain the magnetic head from moving during transportation. Therefore, it has been necessary to provide the magnetic disk apparatus with an additional mechanism, such as a shipping clamp mechanism or the like, which has imposed restrictions upon the manufacturer in designing the magnetic disk apparatus and entailed disadvantages such as increase in cost. Furthermore, the addition of such a mechanism, which is unnecessary to the users, deteriorated the reliability of the apparatus and the users were bothered by the troublesome operation of the shipping clamp mechanism.
  • FIG. 1 is a plan view showing a conventional magnetic head actuating mechanism as applied to a magnetic disk apparatus
  • FIG. 2 is a plan view showing a magnetic head actuating mechanism, in a preferred embodiment, according to the present invention, as applied to a magnetic disk apparatus.
  • FIG. 2 there are shown a magnetic disk 11, a magnetic head 12, an actuator arm 13, a pivot 14 on which the actuator arm 13 turns, a capstan 15 attached to the shaft of a driving motor, and a thin metallic band 16.
  • the practically lengthwise middle part of the metallic band 16 is driven by the circumference of the capstan 15, one end thereof is fixed to the actuator arm 13 and the other end thereof is fixed to a leaf spring 17 for preloading the band 16.
  • a reference character T D designates the dead torque of the driving motor while the same is not energized
  • R 1 designates the radius of the capstan
  • R 2 designates the distance between the center of the pivot 14 and a part where the band 16 is fixed to the actuator arm 13.
  • the actuator arm assembly including the magnetic head 12 and the leaf spring 17, of the magnetic head actuating mechanism of the present invention is constructed so that the moment of the unbalanced mass of the actuator assembly about the pivot 14 is smaller than a predetermined value. That is, the actuator assembly is constructed so that the moment of the unbalanced mass thereof about the pivot 14 upon the application of the maximum disturbance within the range certified for the apparatus to the apparatus while the driving motor is not energized is capable of being countervailed by the dead torque T D of the driving motor.
  • the ordinary maximum disturbance is, at the most, 30G that works on the apparatus when the same is dropped as packed.
  • the maximum moment of the unbalanced mass M of the actuator assembly about the pivot 14 capable of being counterbalanced by the dead torque T D of the driving motor to retain the actuator arm 13 stationary is expressed by:
  • T D is the dead torque of the driving motor
  • R 1 is the radius of the capstan
  • R 2 is the distance between the center of the pivot 14 of the actuator arm 13 to a part where the band 16 is fixed to the actuator arm 13
  • K is a disturbance that works on the apparatus
  • the thickness of the band 16 is neglected.
  • the actuator arm 13 of this embodiment is illustrated as a single and unitary member, the actuator arm 13 may be a composite member consisting of members of different metals having different specific weights, to adjust the moment of the unbalanced mass thereof about the pivot 14 appropriately.
  • the moment of the unbalanced mass of an assembly including the magnetic head about the pivot on which the assembly turns is smaller than a predetermined moment of mass; therefore, the magnetic head is held stationary even if an expected disturbance is applied to the apparatus including the assembly. Accordingly, any magnetic head locking mechanism which has been necessary for an apparatus of this kind need not be provided, the apparatus can be manufactured at a reduced cost, the magnetic head can be retained at a correct position regardless of the manner of placement of the apparatus, and the accuracy of the apparatus is improved.

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  • Moving Of Heads (AREA)

Abstract

A magnetic head actuating mechanism including a capstan attached to the shaft of a magnetic head driving motor, and an actuator arm supported on a pivot, adapted to be turned through a thin metallic band by the capstan and mounted fixedly at one end thereof with at least one magnetic head. The magnetic head actuating mechanism is designed so that the moment of the unbalanced mass of the turning assembly thereof about the pivot is within the predetermined range. The magnetic head is held stationary even while the magnetic head driving motor is not energized. Thus, the magnetic head actuating mechanism obviates the injurious state of contact between the magnetic head and a magnetic disk easily and need not have any magnetic head locking mechanism.

Description

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a magnetic head actuating mechanism for a magnetic disk apparatus or the like, and more particularly to a magnetic head actuating mechanism for actuating a rotary magnetic head which moves along a circular arc on a pivot.
2. Description of the Prior Art
A mechanism of this type such as shown in FIG. 1 has heretofore been proposed. In FIG. 1, there are shown a magnetic disk 1, a magnetic head 2 which is floated slightly over the magnetic disk 1 as the magnetic disk rotates, to write data in or to read data from the magnetic disk 1, an actuator arm 3 mounted with the magnetic head 2 and adapted to turn on a bearing 4, and a capstan 5 mounted on the shaft of a driving motor. When the shaft of the driving motor rotates, the capstan 5 winds or unwinds a thin metallic band 6. One end of the band 6 is fixed to a leaf spring 7 for preloading the band 6 and the other end of the band 6 is fixed to the actuator arm 3.
The action of this magnetic head actuating mechanism will be described hereinafter. Upon the actuation of the magnetic disk 1 for rotation, the magnetic head 2 is floated up by a distance of approximately 0.5 μm for reading or writing data. After the magnetic head 2 has been floated up, the capstan 5 is rotated to move the magnetic head 2 to bring the magnetic head 2 into alignment with each one of the data tracks formed in concentric circles on the magnetic disk 1. The magnetic head 2 moves along a circular arc on the bearing 4 of the actuator arm 3.
The movement of the magnetic head 2 in the direction of the data track as indicated by arrows A and B with the magnetic head 2 in contact with the magnetic disk 1 will possibly destroy the data stored in the magnetic disk 1. Therefore, the magnetic head 2 should never be moved while it is in contact with the magnetic disk 1.
This is also true when power is not supplied to the magnetic disk apparatus, and hence the magnetic disk apparatus needs to be equipped with some protective mechanism which is capable of checking the movement of the magnetic head 2 even if a disturbance within a range certified for the apparatus is applied to the apparatus. Usually, in the case of an apparatus of this kind, the maximum disturbance is such a shock as applied to the apparatus when the packed apparatus is dropped from a predetermined height, and the maximum disturbance is as large as around 30 G. According to a usual protective mechanism for restraining the movement of the magnetic head 2 during transportation, which have most commonly been employed, the magnetic head 2 is placed at a shipping position outside the data area during transportation and, in many cases, the magnetic head 2 is held at the shipping position by means of a locking mechanism.
Since the conventional magnetic disk apparatus is constituted as described hereinbefore, some protective mechanism has been necessary to restrain the magnetic head from moving during transportation. Therefore, it has been necessary to provide the magnetic disk apparatus with an additional mechanism, such as a shipping clamp mechanism or the like, which has imposed restrictions upon the manufacturer in designing the magnetic disk apparatus and entailed disadvantages such as increase in cost. Furthermore, the addition of such a mechanism, which is unnecessary to the users, deteriorated the reliability of the apparatus and the users were bothered by the troublesome operation of the shipping clamp mechanism.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a useful magnetic head actuating mechanism eliminated of the above-mentioned disadvantages of the conventional magnetic head actuating mechanism.
It is another object of the present invention to provide a magnetic head actuating mechanism of a simple construction and a reduced cost which need not be provided with any shipping clamp mechanism.
It is a further object of the present invention to provide a magnetic head actuating mechanism of high accuracy and optimum constitution capable of retaining the magnetic head at a correct position regardless of the manner of placement of the magnetic disk apparatus.
Other objects, features and advantages of the present invention will become apparent from the detailed description of a preferred embodiment thereof taken in conjunction with the accompanied drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view showing a conventional magnetic head actuating mechanism as applied to a magnetic disk apparatus; and
FIG. 2 is a plan view showing a magnetic head actuating mechanism, in a preferred embodiment, according to the present invention, as applied to a magnetic disk apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the present invention will be described in connection with the drawings. In FIG. 2, there are shown a magnetic disk 11, a magnetic head 12, an actuator arm 13, a pivot 14 on which the actuator arm 13 turns, a capstan 15 attached to the shaft of a driving motor, and a thin metallic band 16. The practically lengthwise middle part of the metallic band 16 is driven by the circumference of the capstan 15, one end thereof is fixed to the actuator arm 13 and the other end thereof is fixed to a leaf spring 17 for preloading the band 16. In FIG. 2, a reference character TD designates the dead torque of the driving motor while the same is not energized, R1 designates the radius of the capstan 15, and R2 designates the distance between the center of the pivot 14 and a part where the band 16 is fixed to the actuator arm 13.
The actuator arm assembly, including the magnetic head 12 and the leaf spring 17, of the magnetic head actuating mechanism of the present invention is constructed so that the moment of the unbalanced mass of the actuator assembly about the pivot 14 is smaller than a predetermined value. That is, the actuator assembly is constructed so that the moment of the unbalanced mass thereof about the pivot 14 upon the application of the maximum disturbance within the range certified for the apparatus to the apparatus while the driving motor is not energized is capable of being countervailed by the dead torque TD of the driving motor.
More concretely, the ordinary maximum disturbance is, at the most, 30G that works on the apparatus when the same is dropped as packed. The maximum moment of the unbalanced mass M of the actuator assembly about the pivot 14 capable of being counterbalanced by the dead torque TD of the driving motor to retain the actuator arm 13 stationary is expressed by:
M≦1/K×R.sub.2 /R.sub.1 ×T.sub.D
where TD is the dead torque of the driving motor, R1 is the radius of the capstan, R2 is the distance between the center of the pivot 14 of the actuator arm 13 to a part where the band 16 is fixed to the actuator arm 13, K is a disturbance that works on the apparatus, and the thickness of the band 16 is neglected. When the actuator assembly is designed so that the inequality shown above is satisfied, the magnetic head 12 can be retained stationary even if a disturbance of the above-mentioned magnitude is applied to the apparatus while the driving motor is not energized, and thereby the movement of the magnetic head 12 relative to the magnetic disk 11 while the magnetic head 12 is in contact with the magnetic disk 11, which is injurious both to the magnetic disk 11 and to the magnetic head 12, can easily be obviated.
Although the actuator arm 13 of this embodiment is illustrated as a single and unitary member, the actuator arm 13 may be a composite member consisting of members of different metals having different specific weights, to adjust the moment of the unbalanced mass thereof about the pivot 14 appropriately.
Thus, according to the present invention, the moment of the unbalanced mass of an assembly including the magnetic head about the pivot on which the assembly turns is smaller than a predetermined moment of mass; therefore, the magnetic head is held stationary even if an expected disturbance is applied to the apparatus including the assembly. Accordingly, any magnetic head locking mechanism which has been necessary for an apparatus of this kind need not be provided, the apparatus can be manufactured at a reduced cost, the magnetic head can be retained at a correct position regardless of the manner of placement of the apparatus, and the accuracy of the apparatus is improved.

Claims (2)

What is claimed is:
1. A magnetic head actuating mechanism comprising a magnetic head and a motor for driving said magnetic head, said motor including a shaft, a capstan attached to said shaft, a pivot and an actuator arm mounting said head and supported on said pivot for turning thereon, a metallic band driven by said capstan, said metallic band being fixed to said actuator arm, characterized in that the moment of the unbalanced mass which turns about the pivot satisfies an inequality:
M≦1/K×R.sub.2 /R.sub.1 ×T.sub.D
where M is the moment of the unbalanced mass of the assembly about the pivot, TD is the dead torque of the driving motor, K is the magnitude of a disturbance that works on the apparatus, R1 is the radius of the capstan, and R2 is the distance between the center of the pivot on which the actuator arm turns and the point at which said metallic band is attached to said actuator arm.
2. A magnetic head actuating mechanism according to claim 1, wherein said actuator arm is a single composite member consisting of different metals having different specific weights.
US06/717,137 1984-03-29 1985-03-28 Magnetic head actuating mechanism constructed to minimize address effect of disturbance thereto Expired - Fee Related US4652953A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59061602A JPS60205874A (en) 1984-03-29 1984-03-29 Actuator mechanism of magnetic head
JP59-61602 1984-03-29

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US4652953A true US4652953A (en) 1987-03-24

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4805056A (en) * 1986-08-01 1989-02-14 Mitsubishi Denki Kabushiki Kaisha Magnetic disc drive
US4833557A (en) * 1986-10-23 1989-05-23 Canon Kabushiki Kaisha Transducer shifting device
US5396385A (en) * 1990-07-27 1995-03-07 Mitsumi Electric Co., Ltd. Floppy disk drive
WO2000063891A2 (en) * 1999-04-21 2000-10-26 Seagate Technology Llc Actuator latch for disc drive
US6264472B1 (en) 1999-08-10 2001-07-24 Gc Corporation Method for setting dental glass ionomer cement
US20070081275A1 (en) * 2005-10-12 2007-04-12 Chun Jeong-Il Actuator and hard disk drive having the same

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01130365A (en) * 1987-11-17 1989-05-23 Mitsubishi Electric Corp Magnetic head positioning mechanism for magnetic disk device
GB2235330A (en) * 1989-06-20 1991-02-27 Tokico Ltd Magnetic disc apparatus
EP0645762A1 (en) * 1993-09-21 1995-03-29 Hewlett-Packard Company Rotary inertia latch for latching a rotary actuator in a disk drive

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1145536A (en) * 1965-06-29 1969-03-19 Electroacustic Gmbh Improvements in or relating to traversing mechanisms for record playback arms of recording machines
US3500363A (en) * 1966-07-11 1970-03-10 Singer Co Scanning apparatus
US4164769A (en) * 1978-04-24 1979-08-14 Data General Corporation Cross band coupling for stepper-motor-driven, rigid magnetic disc
US4164766A (en) * 1978-04-24 1979-08-14 Data General Corporation Disc memory apparatus magnetic head carriage manual control
EP0049946A2 (en) * 1980-10-15 1982-04-21 Minnesota Mining And Manufacturing Company Apparatus for positioning a transducer with respect to a track
JPS5958669A (en) * 1982-09-28 1984-04-04 Nippon Shiyuuhenki Kk Rotary head access device

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1145536A (en) * 1965-06-29 1969-03-19 Electroacustic Gmbh Improvements in or relating to traversing mechanisms for record playback arms of recording machines
US3500363A (en) * 1966-07-11 1970-03-10 Singer Co Scanning apparatus
US4164769A (en) * 1978-04-24 1979-08-14 Data General Corporation Cross band coupling for stepper-motor-driven, rigid magnetic disc
US4164766A (en) * 1978-04-24 1979-08-14 Data General Corporation Disc memory apparatus magnetic head carriage manual control
EP0049946A2 (en) * 1980-10-15 1982-04-21 Minnesota Mining And Manufacturing Company Apparatus for positioning a transducer with respect to a track
JPS5958669A (en) * 1982-09-28 1984-04-04 Nippon Shiyuuhenki Kk Rotary head access device

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4805056A (en) * 1986-08-01 1989-02-14 Mitsubishi Denki Kabushiki Kaisha Magnetic disc drive
US4833557A (en) * 1986-10-23 1989-05-23 Canon Kabushiki Kaisha Transducer shifting device
US5396385A (en) * 1990-07-27 1995-03-07 Mitsumi Electric Co., Ltd. Floppy disk drive
WO2000063891A2 (en) * 1999-04-21 2000-10-26 Seagate Technology Llc Actuator latch for disc drive
WO2000063891A3 (en) * 1999-04-21 2001-05-10 Seagate Technology Llc Actuator latch for disc drive
GB2363670A (en) * 1999-04-21 2002-01-02 Seagate Technology Llc Actuator latch for disc drive
US6264472B1 (en) 1999-08-10 2001-07-24 Gc Corporation Method for setting dental glass ionomer cement
US20070081275A1 (en) * 2005-10-12 2007-04-12 Chun Jeong-Il Actuator and hard disk drive having the same

Also Published As

Publication number Publication date
GB2157052B (en) 1988-06-08
GB2157052A (en) 1985-10-16
JPS60205874A (en) 1985-10-17
GB8507874D0 (en) 1985-05-01

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